Technical Field
The invention relates to vibration generators for generating vibrations and to electronic devices having the vibration generators.
Background Art
Japanese Unexamined Patent Publication No. 2010-27613 discloses a conventional vibration generator including a plastic frame, a coil, a stationary pole, and a movable pole. The plastic frame of ring shape has a central open part, which houses the coil, the stationary pole, and the movable pole. The stationary pole is a generally L-shaped magnetic member having a long leg and a short leg. The long leg of the stationary pole is received in the coil and has first and second lengthwise ends fixed to the plastic frame. The short leg of the stationary pole extends perpendicularly from the first lengthwise end of the long leg of the stationary pole. The movable pole is a generally L-shaped magnetic member (plunger) having a long leg and a short leg. The long leg of the movable pole extends in parallel with the long leg of the stationary pole and has first and second lengthwise ends fixed to the plastic frame. The first lengthwise end of the long leg of the movable pole is opposed to the short leg of the stationary pole with a gap therebetween. The short leg of the movable pole extends perpendicularly from the second lengthwise end of the long leg of the movable pole and is opposed the second end of the long leg of the stationary pole with a gap therebetween.
When the coil is energized with electric current, the movable pole is magnetically attracted toward the stationary pole to elastically deform the plastic frame. When the coil is de-energized, the coil stops magnetically attracting the movable pole to allow restoration of the plastic frame. When the coil continues to be alternately energized and de-energized, the plastic frame is elastically deformed and restored alternately to generate vibrations.